Many types of spinal irregularities can cause pain, limit range of motion, or injure the nervous system within the spinal column. These irregularities can result from, without limitation, trauma, tumor, disc degeneration, and disease. Often, these irregularities are treated by immobilizing a portion of the spine. This treatment typically involves affixing a plurality of screws and/or hooks to one or more vertebrae and connecting the screws or hooks to an elongate rod that generally extends in the direction of the axis of the spine.
Treatment for these spinal irregularities often involves using a system of pedicle screws and rods to attain stability between spinal segments. Instability in the spine can create stress and strain on neurological elements, such as the spinal cord and nerve roots. In order to correct this, implants of certain stiffness can be implanted to restore the correct alignment and portion of the vertebral bodies. In many cases, an anchoring member such as a pedicle screw along with a vertical solid member can help restore spinal elements to a pain free situation, or at least may help reduce pain or prevent further injury to the spine.
As the science and technology of spine surgery continues to progress, there is an increasing interest in developing alternative, minimally invasive, methods to conventional “open” spine surgery. The goals of these less invasive alternatives are to avoid the surgical exposure, dissection, and retraction of muscles and tissues that is necessary with “open” surgery. In general, a minimally invasive spine surgery system should be able to perform the same procedure as the traditional open technique, but through smaller incisions instead of one longer incision. As a result, some physicians feel that using a minimally invasive spine surgery system generally causes less soft tissue damage, reduces blood loss and reduces recovery time. In addition, patients generally prefer the smaller scars that are left using a minimally invasive approach.
Historically, spine fusion surgery including pedicle screw fixation with deep placement of rods has been one area that has presented significant challenges for minimally invasive approaches. However, advancement in technologies such as fluoroscopy and improvements in optics have contributed to the advent of a few minimally invasive spine fusion surgery techniques.